The wireless network Eduroam at UiO is free for you as a student, and far more environmentally friendly than using 4G or 5G. It is an encrypted and secure network that you log on to with your username and password, and which your phone and computer will connect to automatically when you are on campus.
To use Eduroam, you'll need to download a configuration file from the link above. Once you have Eduroam, you can also get online at many research and educational institutions in Norway and elsewhere in Europe.